1. Technical Field of the Invention
This invention relates generally to infrared communication systems and more particularly to detecting types of infrared (IR) transceivers in such IR communications systems.
2. Description of Related Art
IR systems are known to include IR transceivers in communication via IR communication paths. Each IR transceiver includes a light generating diode and a light receiving diode. Such IR communication may conform to a standard or to a propriety protocol.
One IR standard is provided by the Infrared Data Association (“IrDA”). IrDA defines a specification titled “Serial Interface for Transceiver Control,” published Mar. 29, 2000. This specification provides a standard command set for communications between an IR controller and an IR transceiver, and particular responses to the command set, depending on the device.
There are various types of infrared transceiver devices on the market, including some transceiver devices conforming to the IrDA serial interface specification, such as Vishay Semiconductor device TFDU8102. Some don't conform to the IrDA serial interface specification, such as “TEMIC style” devices. Examples of these non-conforming (or TEMIC style devices) include the TFDU6102 marketed by Vishay Semiconductors, the ZHX2010 device marketed by Zilog, and the GP2W1001YP device marketed by Sharp Electronics.
When designing circuitry for connecting an IR transceiver chip to an IR controller, the circuit designer was required to hard wire the IR controller with a transceiver device type (to select a transceiver communication protocol) by setting a pin on a chip. Alternatively, the circuit designer was required to manually program the IR controller chip to communicate with a specific IR transceiver type, for example, by writing to a flash memory or EEPROM to program the communication protocol for the particular transceiver type. These extra steps in the design and manufacturing process are clearly laborious and require a design change in IR device circuitry each time a different IR transceiver is selected to be used with the IR controller. Another issue is that once the transceiver is set, it cannot be changed without human interaction. As such, IR manufacturers typically include multiple products to cover the various protocols, which add to cost.
Therefore, a need exists for a method and apparatus of detecting an IR transceiver type without the above-referenced limitations.